The present invention relates to a new and improved construction of a breechblock for an automatic firing weapon or gun.
The breechblock of the present invention is of the type comprising a breechblock housing have a bore in which there is secured the barrel of the weapon, a breechblock body displaceable in the breechblock housing, the breechblock body being provided with at least one blocking body by means of which the breechblock body can be locked with the breechblock housing, and the blocking body is supportable at a rest or arresting surface of a locking body inserted into the breechblock housing.
According to a prior art construction of breechblock employed at a firing weapon the breechblock housing possesses arresting or locking grooves for the blocking bodies. The markedly loaded arresting surfaces of such grooves are not arranged at the breechblock housing itself, rather at locking bodies constructed in the form of bolts and formed of wear resistant material of high strength. These bolts are mounted in bores in the breechblock housing which are directed in skewed fashion perpendicular to the lengthwise axis of the weapon. To secure such against rotation the bolts in each case are equipped with a wedge or key and the bores with a fitting groove or keyway.
By virtue of the arrangement of arresting grooves in the breechblock housing, but particularly due to the arrangement of the transversely directed bores with the grooves or keyways for the locking bodies, the breechblock housing is appreciably weakened. Upon loading the breechblock housing due to the back pressure of the cartridge sleeve during firing of the weapon, there is formed, as is known, a high concentration of stress at the region of the locking bolts, resulting in an increased danger or rupture of the breechblock housing. It is for this reason that the breechblock housing must be dimensioned to be appreciably thicker at this region, which, disadvantageously, leads to considerable increase in weight. The breechblock housing additionally has a rather complicated shape. Internally thereof there must be formed, apart from the usual openings for the weapon barrel and for the breechblock, also the aforementioned arresting or locking grooves and the bores with the grooves or keyways for the locking bodies. Since high requirements are placed upon the precision of the locking device, the fabrication and assembly of the weapon is expensive. The manufacture of the arresting grooves in the breechblock housing is additionally only then without problem, if the breechblock housing is either open at one end or constructed as a bipartite member.